The present invention relates to image recording devices receptive of a video signal from a host device, such as computer, for recording or printing an image which may be normally displayed by a CRT display device controlled through the host device.
FIG. 7 illustrates the recording operation of the conventional recording device, in which image data is transferred to the recording device in the form of a video signal. At first, a desired image is held in the host device, and a video signal line is connected to the recording device. Then, a request or command signal is inputted into the recording device from the host device so as to enable the recording device. Thereafter, the recording device starts to receive image data representative of the held image in the form of a video signal through the connected signal line. The recording device counts a predetermined period of time in response to the command signal such that the image data is transferred within the period and the image is also held during the period. Alternately, the operator watches a printing unit of the recording device and holds the connection of the signal line until the operator recognizes the completion of image recording.
However, in the prior art, a transfer interval of the image data in the form of the video signal is not uniformly determined, but is varied according to the scanning timing of the video signal and gradation levels of the image to be recorded. Thus the predetermined period is determined sufficiently long to cover the variable transfer interval, thereby causing the problem that redundant time is consumed during the image data transfer.
Further, it may happen that the recording device may have trouble incidentally so that the recording device can not receive or admit the transmitted video signal. In such case, there is caused the problem that the host device inadvertently transfers the image data which can not be recorded safely by the recording device.
Furthermore, in the case that the operator controls the image data transfer while watching the printing unit of the recording device, there is the caused problem that the operation is time consuming and inconvenient when the host device and the recording device are located away from each other.